by Joe Farina » Wed Jan 13, 2021 8:48 am
Nice repeat. Without considering the stability of the laser, so many things can be refined and experimented with, in regards to DCG. Film formulas, coating methods, and the all-important processing technique.
Your laser is unstable, but I wouldn't be concerned with it, for now. Those dark bands across the chest of the object are so-called "depth contours" (this is also known as the sliced bread effect). The laser is changing wavelength slightly during the length of the 5-minute exposure.
Lasers are the perpetual problem of the holographer. When the time comes for a better laser (and you no longer want to see the dark bands), I would suggest a Coherent 315M-100, which is a ~100mW 532nm laser. They are usually on eBay:
https://www.ebay.com/itm/Coherent-DPSS- ... SwjwdeQuTi
Of all the lasers I've used, this has proven to be the best and most reliable for holography. I'm still using the one I bought ~15 years ago. I'm still curious about the actual output of your laser. If it's a high output laser, much more than 100mW, then that might be contributing to your success. I've only worked with blue-exposed DCG, or dye-sensitized DCG with 532/633nm. With the dye-sensitized DCG (which is complicated), even 30mW of green light is enough. But I don't know what your film formula requires. Dave B. has done a lot of work with 532nm DCG, it might be worthwhile to review his posts on this forum, and get a better idea on how much 532nm light you need with your film formula.
Although I haven't tried these myself, this may be a good bet for a new laser (from Dave B.), and it has the benefit of being very inexpensive:
https://www.ebay.com/itm/Osram-Green-La ... OSw889eNC1~
Good luck, and I look forward to seeing more of your results.
Nice repeat. Without considering the stability of the laser, so many things can be refined and experimented with, in regards to DCG. Film formulas, coating methods, and the all-important processing technique.
Your laser is unstable, but I wouldn't be concerned with it, for now. Those dark bands across the chest of the object are so-called "depth contours" (this is also known as the sliced bread effect). The laser is changing wavelength slightly during the length of the 5-minute exposure.
Lasers are the perpetual problem of the holographer. When the time comes for a better laser (and you no longer want to see the dark bands), I would suggest a Coherent 315M-100, which is a ~100mW 532nm laser. They are usually on eBay:
https://www.ebay.com/itm/Coherent-DPSS-532nm-laser-100mW-SLM-single-mode-120mW-tested-DPY315M-100/164265273211?hash=item263ef9277b:g:l4EAAOSwjwdeQuTi
Of all the lasers I've used, this has proven to be the best and most reliable for holography. I'm still using the one I bought ~15 years ago. I'm still curious about the actual output of your laser. If it's a high output laser, much more than 100mW, then that might be contributing to your success. I've only worked with blue-exposed DCG, or dye-sensitized DCG with 532/633nm. With the dye-sensitized DCG (which is complicated), even 30mW of green light is enough. But I don't know what your film formula requires. Dave B. has done a lot of work with 532nm DCG, it might be worthwhile to review his posts on this forum, and get a better idea on how much 532nm light you need with your film formula.
Although I haven't tried these myself, this may be a good bet for a new laser (from Dave B.), and it has the benefit of being very inexpensive:
https://www.ebay.com/itm/Osram-Green-Laser-System-Driver-optics-Holography-50-mW-SLM-Coherent-Lasos/233833122288?hash=item36718a49f0:g:FckAAOSw889eNC1~
Good luck, and I look forward to seeing more of your results.